A process to support a homogeneous catalyst on a porous solid support is performed in two separate zones. In the first zone the solid is contacted, under stirring, with an amount of a catalyst solution lower than the total pore volume of the solid. In the second zone the solid is dried from the solvent while flowing under pneumatic conveying. A loop circulation of solid is established between the two zones, so that the solid is subject to more contacting steps. The process is particularly suitable to support a metallocene-alumoxane polymerization catalyst on a porous prepolymer. The process can be advantageously performed in continuous, thus fitting the needs of an industrial scale production process.